Introduction to the new mainframe Chapter 10 Topics in z/os system programming

Transcription

1 Chapter 10 Topics in z/os system programming

2 Objectives In this chapter you will learn to: Discuss the responsibilities of a z/os system programmer Explain system libraries, their use, and methods for managing their content Configure consoles IPL a system 2

3 Key terms HCD IODF SYSRES SMP/E LNKLST IPL WTOR PARMLIB PROCLIB system symbols PSA LPA nucleus LOADPARM SQA 3

4 Considerations for a new application New batch applications i to scheduler New JCL procedures to procedure library Document operational procedures Security privileges Add load libraries to system Automation Reload system (if required) 4

5 What is systems programming? A systems programmer installs, customizes and maintains the operating system To do this they need knowledge of Hardwareare o Storage o Processor Software o System libraries and data sets Current customization ti 5

6 System programming overview System performance and workload management SYSTEM PROGRAMMING Security, Availability and Integrity System parameters and system libraries management Controlling operating activities and functions z/os new features implementation and z/os system maintenance iodfxx Hardware I/O configuration 6

7 z/os operational system administration is: Software installation and maintenance Customize parameters System libraries for software System data sets z/os system address spaces and subsystems Real and virtual storage 7

8 z/os Workload Manager Workload manager (WLM) is an address space which manages the tasks running on the system Uses an installation-defined policy to determine relative priority of competing workloads WLM can also be used to manage hardware resources 8

9 System performance System tuning is constant and iterative Only a real problem when resources are constrained WLM is one component Can only manage what is set up Initial set up of initiators and other resources plays a great part 9

10 Job flow Job entry subsystem (JES) controls job flow Receives jobs into system Initiates the job Controls initial output processing 10

11 I/O device management Input/output device configuration must be defined to both hardware and software HCD is used to build an I/O definition file This definition can be activated to both software and hardware dynamically Sometimes major changes require an IPL of software or POR of hardware 11

12 Security Protection of data against unauthorized disclosure, transfer, modification or destruction Systems programmer installs and maintains the security system 12

13 Integrity Designed, implemented and maintained to protect against unauthorized access Unauthorized software must not be able to access authorized states Unauthorized software must not be able to bypass system security such as RACF 13

14 Availability System availability is designed to be very high Many systems require 24 hour 7 day operation 14

15 Change control I/T organizations achieve their goals through disciplined change management processes and policy enforcement These goals include: High service availability Increased security Audit readiness Cost savings 15

16 z/os operation This is the day to day management of the operating environment both software and hardware Operator interaction is message and command based Automated processing of the messages and commands is available and operators now manage by exception 16

17 z/os Production Control Build batch schedules Promote programs to production Investigate batch failures 17

18 z/os system libraries z/os software Customization data Non-z/OS (CICS, DB2) Mainframe User defined exits Non-IBM software User data 18

19 Types of data z/os software on SYSRES volumes Non-z/OS software e.g. CICS Non-IBM software Customization data parmlib, IODF User exits User data often the largest pool of volumes 19

20 z/os system libraries These are the most important system libraries SYS1.LINKLIB prime system software library SYS1.LPALIB system subroutines SYS1.NUCLEUS basic supervisor modules SYS1.PROCLIB system procedure JCL SYS1.PARMLIB control parameters 20

21 SYS1.LINKLIB SYS1.LINKLIB is the main software library LNKLST concatenation is a group of system and user-defined libraries which form part of the system search order for load modules Not all on one volume 21

22 System search order for programs Programs (load modules) must be in central storage and therefore in the virtual storage of the address space before they can run System has a defined search order for a newly requested program 22

23 Search order for programs STEPLIB if present JOBLIB if present and no STEPLIB Link Pack Area (LPA) o Dynamic LPA modules o Fixed LPA o Modified LPA o Pageable LPA Linklist 23

24 Overview of LNKLST LNKLST SET System Data Sets SYS1.LINKLIB SYS1.MIGLIB SYS1.CSSLIB Search order Other Load Libraries 24

25 Using PROGxx to define LNKLST A LNKLST set is an ordered list of datasets for processing as the LNKLST concatenation The PROGxx member may be used to define other lists as well as the linklist The linklist must be: o Defined o Have libraries added o Activated 25

26 Example linklist definition: LNKLST DEFINE NAME(LNKSYSA) COPYFROM(CURRENT) LNKLST ADD NAME(LNKSYSA) DSNAME(SYS1.PROD.LOADLIB) LNKLST ADD NAME(LNKSYSA) DSNAME(SYS1.TEST.LOADLIB) LNKLST ACTIVATE NAME(LNKSYSA) 26

27 LLA and VLF Library LookAside is an address space which maintains a copy of the directories of selected libraries to improve performance By default, LLA always caches the linklist directories Virtual Lookaside Facility is another address space which caches the most popular modules which reduces fetch time VLF can also cache other data objects such as RACF tables to improve response 27

28 Libraries and members at IPL time An number of libraries must be present for the system to load at IPL time SYS1.PARMLIB contains the required definitions SYSn.IPLPARM searched for LOADxx SYS1.LPALIB SYS1.PROCLIB SYS1.NUCLEUS 28

29 LOADxx LOADPARM defines the address of the IODF and the suffix of fthe LOADxx member At IPL the system searches for LOADxx in: SYS0.IPLPARM SYS9.IPLPARM on IODF volume SYS1.PARMLIB on the IODF volume SYS1.PARMLIB on the IPL volume 29

30 LOADxx The LOADxx member specifies: The IODF data set name The master catalog name and volume The parmlib concatenation The IEASYSxx member to use 30

31 Defining a logical parmlib Loadxx IODF 00 SYS6 MOEMVSP1 01 Y SYSCAT MPAT1113CATALOG.MCAT.VMPCAT1 HWNAME P201 LPARNAME A1 PARMLIB SYS0.IPLPARM PARMLIB SYS1.OS390R7.PARMLIB PARMLIB SYSPROG.SYS1.PARMLIB Parmlib concatenation SYS0.IPLPARM SYS1.OS390R7.PARMLIB SYSPROG.SYS1.PARMLIB SYS1.PARMLIB Search order 31

32 IEASYSxx This is the main parameter member for z/os IEASYS00 is used by default If essential parameters are not specified then the operator will be prompted Normally all parameters are specified to avoid inconsistent operator response 32

33 Parmlib commands The parmlib concatenation can be displayed using D PARMLIB The parameters used at IPL can be displayed using D IPLINFO The parmlib concatenation can be modified dynamically using SETLOAD xx,parmlib 33

34 Commands to DISPLAY PARMLIB D PARMLIB IEE251I PARMLIB DISPLAY 377 PARMLIB DATA SETS SPECIFIED AT IPL ENTRY FLAGS VOLUME DATA SET 1 S TOTSY1 SYS1.SYSPROG.PARMLIB 2 D TOTSY1 SYS1.PARMLIB 3 S Z04CAT CPAC.PARMLIB 4 S Z04RE1 SYS1.IBM.PARMLIB D IPLINFO IEE254I IPLINFO DISPLAY 379 SYSTEM IPLED AT ON 07/23/2004 RELEASE z/os LICENSE = z/os USED LOADR2 IN SYS0.IPLPARM ON 3800 ARCHLVL = 2 MTLSHARE = N IEASYM LIST = XX IEASYS LIST = (R3,04) (OP) IODF DEVICE 3800 IPL DEVICE 8038 VOLUME Z04RE1 34

35 SYS1.LPALIB The Link Pack Area (LPA) is built at IPL time from the modules defined in the LPALSTxx member of parmlib. SYS1.LPALIB is always the first library used unless overridden by a SYSLIB statement Modules are loaded into common storage at IPL time and so are available to all address spaces 35

36 SYS1.LPALIB Fixed LPA comprises those modules defined in IEAFIXxx that are fixed in central storage Pageable LPA comprises most other modules whose pages are eligible to be stolen Modified LPA has modules which are temporary replacements for PLPA modules and is searched first. 36

37 Example of LPALST member File Edit Edit_Settings Menu Utilities Compilers Test Help EDIT SYS1.PARMLIB(LPALST5B) Columns Command ===> Scroll ===> CSR ******** ***************************** Top of Data ************** SYS2.LPALIB, SYS1.LPALIB, SYS1.SERBLPA, SDF2.V1R4M0.SDGILPA, SYS1.SIATLPA, ING.SINGMOD3, NETVIEW.SCNMLPA1, REXX.V1R3M0.SEAGLPA, ISF.SISFLPA, EOY.SEOYLPA, SYS1.SBDTLPA, CEE.SCEELPA, ****** **************************** Bottom of Data ************** 37

38 IEAFIX member File Edit Edit_Settings Menu Utilities Compilers Test Help EDIT SYS1.PARMLIB(IEAFIX01) Columns Command ===> Scroll ===> CSR ******** ***************************** Top of Data ********************** INCLUDE LIBRARY(SYS1.LPALIB) MODULES (IEAVAR00, /* 7K RCT INIT/TERM */ IEAVAR06, /* RCT INIT/TERM ALIAS */ IGC001G, /* 456 RESTORE(SVC17) */ ICHRFC00, /* RACF IMS/CICS */ ICHRFR00) /* RACF IMS/CICS */ INCLUDE LIBRARY(SYS1.SVCLIB) MODULES(IGC09302) ************************************** Bottom of Data ******************* 38

39 SYS1.PROCLIB When the system is first IPL d either the MSTJCL00 load module or MSTJCLxx in SYS1.PARMLIB is used to provide the JCL for the master scheduler This JCL at a minimum points to SYS1.PROCLIB to provide the JCL procedures for the required tasks to run the system 39

40 Sample master JCL //MSTJCL05 JOB MSGLEVEL=(1,1),TIME=1440 //EXEC PGM=IEEMB860 //STCINRDR DD SYSOUT=(A,INTRDR) //TSOINRDR DD SYSOUT=(A,INTRDR) //IEFPDSI DD DSN=SYS1.PROCLIB,DISP=SHR //IEFPARM DD DSN=SYS1.PARMLIB,DISP=SHR //SYSUADS DD DSN=SYS1.UADS,DISP=SHR //SYSLBC DD DSN=SYS1.BRODCAST,DISP=SHR 40

41 A job s procedure library The JES cataloged procedure in SYS1.PARMLIB contains lists of procedure libraries to be searched for JCL procedures JCLLIB may also be used to specify a private library to be searched first 41

42 Procedure library //PROC00 DD DSN=SYS1.PROCLIB,DISP=SHR SYS1.PROCLIB,DISP SHR // DD DSN=SYS3.PROD.PROCLIB,DISP=SHR //PROC01 DD DSN=SYS1.PROC2,DISP=SHR... //PROCnn DD DSN=SYS1.LASTPROC,DISP=SHR... //MYJOB JOB //MYLIBS JCLLIB ORDER=(MY.PROCLIB.JCL,SECOND.PROCLIB.JCL) JCL) //S1 EXEC PROC=MYPROC

43 System symbols System symbols allow the use of a shared parmlib by two or more systems Each symbol has a name which can be used in various places and then substituted at IPL time Major uses are indirect cataloging and substituting system specific datasets such as the page data sets 43

44 System symbols SYSDEF HWNAME(SCZP801) LPARNAME(A08) SYSNAME(SC04) SYSPARM(R3,04) SYMDEF(&CPCNAME='P801') SYMDEF(&DFHSMHST='ON') SYMDEF(&SYSR2= ZXYSY2 ) SYMDEF(&SYSR3= &SYSR1(1:5).3 ) 44

45 Use of system symbols PAGE=(PAGE.&SYSNAME..&PLPADSN1., PAGE.&SYSNAME..&COMMDSN1., &COMMDSN1 PAGE.&SYSNAME..LOCAL1, PAGE.&SYSNAME..LOCAL2,L) 45

46 Summary The role of the system programmer is to install, customize and maintain the operating system and must be aware of: z/os operational system administration Workload management System performance Job flow I/O device management Security/integrity/availability z/os Operation Change management 46